Conventionally, a pressure sensor is used to detect pressure of a fluid flowing through a passage. Known pressure sensors include an amplifier-embedded type which has an embedded amplifier circuit for amplifying a pressure signal detected by a pressure-detecting unit (e.g., see PTL 1), and a separate type which has no embedded amplifier circuit, but instead transmits a pressure signal to an amplifier circuit provided outside the pressure sensor.
Due to a short length of its wire for transmitting a pressure signal, which is a minute signal, to the amplifier circuit, the amplifier-embedded pressure sensor has an advantage that the pressure signal is less likely to be affected by noise, etc.